1. Field of the Invention
This invention relates to mounting of stone slabs to structures. However it is especially suited to those slabs which are located above windows, or other openings in a building facade, where the bottom of the stone slabs are exposed and where no metal weight relieving objects are permitted beneath the bottom edge of the stone veneer.
2. Description of Prior Art
In the prior art it is possible to suspend and anchor stone slabs with exposed edges above an opening without using exposed metal supports under the bottom edge of the stone veneer. However, the prior art attachments generally depend upon stone liners which are epoxied or glued with other bonding agents to the back of the stone slabs. Because the life expectancy of epoxies and/or the other bonding agents is not yet known and since the proper adhesion of such bonding agents is dependent upon numerous factors including temperature and other atmospheric conditions, as well as the workmanship of the shop or field labor, the prior art has for safety's sake also "nailed" the glued stone liners to the stone slabs. This "nailing" was usually accomplished with metal dowels drilled through the liners into the stone slabs at an angle oblique to the face of the stone slabs. The above described stone liner suspension and anchoring technique has many disadvantages, the major disadvantage being that the technique is very expensive. Also if the technique is performed in the field with field labor sufficient quality control is hardly possible under field conditions. If on the other hand, it is performed in the shop, the technique provides a significant transportation problem due to the mandated expensive packing and high risk of breakage.
Prior art has also used shaped horizontal slots in the back of the stone slabs to receive metal relieving angles or plates for suspension and anchoring. However, this technique is not adoptable to thin veneer and when used in thicker stone slabs, it weakens the stone slabs. Furthermore, its adjustablity is very limited.
Another technique used by prior art consists of tapped and threaded metal plugs drilled in stone slabs for lateral connections and/or for hanging soffits. In both cases the threaded rod which is engaged into the plug, through the back of the stone slab works on tension or compression which, as noted above, are undesirable.
Finally, prior art has used metal angles or other metal shapes attached to stone as a gravity connection. This technique was performed with either expansion bolts - introducing stresses in the stone slabs, or with slightly bent threaded rods epoxied into the back of the stone slabs. However neither the expansion bolt, nor the epoxied bar technique is suitable for thin veneer suspension and retention.